发动机特性计算模型在整车性能计算中的应用

发动机特性模型的建立是进行车辆动力性和燃油经济性模拟计算的基础 ,利用拟合法、综合法和类比法描述了发动机使用特性的数学模型并进行了比较。研究结果表明 ,各类方法简单可靠 ,计算精度符合要求     

自动变速器换挡曲线的研究

本文利用作图法,基于车辆的整车参数、发动机特性参数、变速箱参数,对车辆的动力性和经济性换挡曲线进行了设计;并根据驾驶经验对换挡曲线进行优化。通过仿真计算表明,动力性换挡曲线使车辆具有较好的加速性能;在整车循环工况下,经济性换挡曲线使车辆具有较好的燃油经济性。     

基于Matlab的发动机特性研究

发动机作为汽车的核心部件,决定着整车的性能和品质好坏。针对总质量为6.75 t的中型货车进行发动机特性研究,选择不同功率的3款发动机,利用Matlab绘出外特性曲线,得到不同转矩特性和比油耗特性,进行4次多项式拟合;计算汽车的动力性和经济性,绘制了3款发动机的行驶性能、爬坡性、加速性能以及燃油消耗性曲线,经比较,选用其中一款性能较优的发动机。结果表明,所选用的发动机整车匹配性良好,为评价汽车的动力性和经济性提供了参考。     

基于CRUISE的某轻卡搭载3.2L动力计算与实测符合性

文章以CRUISE计算软件为基础,运用汽车仿真计算方法计算整车动力性经济性,对比计算与实测的偏差。研究理论计算的影响因素,在对比中发现,传动系统的效率、发动机换挡转速对仿真计算影响较大。通过试验测试验证仿真分析的准确性及其不足,剖析影响因素。并通过调整传动系统的效率、换挡转速,发动机外特性和万有特性曲线符合性排查等措施,进一步提升整车动力性、经济性,达成设计要求,为类似设计过程提供参考。     

整车动力性经济性匹配优化设计方法

整车动力性和经济性是一对相互矛盾的整车性能,如何在获得足够动力性的同时,能有最好的燃油经济性是整车匹配中需要解决的问题。随着汽车发动机电子燃油喷射技术的发展,为整车的动力性、经济性匹配提供了良好的条件,使整车匹配中可以根据设计要求,在一定范围内,通过调整发动机外特性和变速箱速比,使整车动力性和经济性达到最优。     

SUV车传动系与高压共轨柴油机的匹配研究

针对某SUV车,运用GT-DRIVE软件分别对给定传动系统时不同配置的柴油机和给定发动机时不同传动系统对整车性能的影响进行仿真分析。结果表明:对一定的传动系统,发动机采用可变增压中冷和EGR,可有效改善整车的动力性、燃油经济性和排放特性;而对确定的发动机,合理选定传动系的传动比,可提高燃油经济性,但将损失部分动力性。     

基于AVL_CRUISE客车动力配置选型仿真分析

文章利用avl_cruise软件对某6730客车建立了整车模型,模拟了发动机、变速箱与三种不同主减速比之间的匹配关系,分别进行了动力性和燃油经济性模拟计算,得到了定制任务下的动力性指标、燃油经济性指标和Highway循环发动机运行工况分布图。依据计算得到的数据绘制了各档最大动力因数、爬坡度图形以及4、5档下不同主减速比等速百公里耗油图。最后综合分析数据和图形得到整车动力性与燃油经济性的合理匹配,为整车前期配套开发提供了依据。     

基于GT—DRIVE的整车动力性燃油经济性仿真

汽车的动力性和燃油经济性是其最基本与最重要的性能之一。为在汽车开发之初分析整车的动力性和燃油经济性,文章研究了动力性和燃油经济性的评价指标,合理选取整车参数,利用GTDRIVE软件对整车进行动力学和运动学建模与仿真计算。将仿真结果与试验结果对比,合理设置边界条件修正模型,最终得到较为精准的模型,使得在没有样车阶段,利用GT—DRIVE软件仿真可以得到整车的动力性和燃油经济性参数,能够对动力系统的匹配方案进行定量评价,为以后汽车的动力系统匹配优化提供一定的理论参考。     

某型越野载货车动力传动系统匹配与优化

本文首先选定动力性、燃油经济性为评价指标,并确定这些指标的目标值;然后依据实际情况,确定升级车型动力传动系统的结构形式和参数,并运用仿真软件,建立了整车仿真模型,对其动力性、燃油经济性进行了模拟计算和讨论,对升级车型的性能进行了实车验证,仿真计算结果和试验结果基本吻合,验证了仿真模型与结果的可信性。根据仿真分析的结果,优化了动力传动系统,并对优化方案重新仿真模拟和实车验证,结果表明,采用优化方案后,整车的动力性能有了明显提升,同时具有良好的燃油经济性能。     

基于Cruise的微卡发动机匹配分析

合适的动力总成对整车动力性、燃油经济性有非常重要的作用,文章利用Cruise仿真软件对匹配某款微卡的几款发动机在不同传动系速比下进行了整车性能分析,在满足整车动力性的前提下,选出了最佳的发动机匹配方案,使燃油经济性最低,并满足了最新的法规油耗限值要求。     

基于SimUlink的整车动力模型构建及拓展

采用Simulink软件建立了整车动力系统模型,通过计算可以获得给定道路环境和车速条件下的发动机动力性能需求,并与AMESim模型的计算结果进行了对比分析。结果表明：Simulink模型具有较高的仿真精度,~AMESim的建模方式更加自由,并便于细化拓展,为发动机细化研究提供了一个很好的平台。     

车用重型柴油机二级增压系统模拟及试验研究

针对某车用重型柴油机进行了二级增压系统匹配研究,根据产品开发目标要求选择了高、低二级增压器。采用GT-Power软件建立了二级增压柴油机仿真模型,并对柴油机外特性稳态工况性能进行了模拟计算,分析了二级增压系统能量分配对柴油机性能的影响规律。建立了二级增压柴油机测试平台,并进行了外特性、万有特性及排放特性试验。模拟及试验结果表明,二级增压系统可以大幅提高柴油机低速扭矩,改善燃油经济性,拓宽柴油机燃油经济性运行区域,大幅降低柴油机PM排放。     

汽车空气动力学的计算机仿真方法

汽车的空气动力特性是汽车的重要性能指标之一。计算流体力学（ＣＦＤ）与汽车空气动力学相结合，产生了一门崭新的技术－汽车空气动力学的计算机仿真。概要介绍了汽车空气动力学计算机仿真技术的意义、理论背景、计算方法和目前国际上应用的现状。     

变海拔环境下的车用柴油机进气压力控制仿真研究

针对车用柴油机运行在高原地区外特性恶化的难题,提出了一种变海拔环境下柴油机进气压力控制方法,该方法通过调节高压级增压器旁通阀流通系数来动态调节二级涡轮可调增压系统压比。在基于最佳空燃比和最大输出功率的柴油机进气压力动态控制仿真基础上,建立了高压级增压器旁通阀流量系数与转速及大气压力的匹配关系。仿真试验表明,该方法大幅度降低了大气压力变化对柴油机外特性的影响,动力性和燃油经济性得到了明显改善。     

基于CFD的整车涉水性能仿真预测

发动机气缸进水将直接导致车辆熄火甚至发动机报废,因此避免发动机进气口水入侵是整车涉水性能开发的关注重点.本文采用流体力学的两相流模型和动网格模型建立整车涉水仿真模型.通过实时监测发动机舱水位高度、发动机进气口的水体积分数和进水量来预测整车涉水性能.对标发动机舱内水位高度的实验与仿真结果,验证了此方法可应用于车辆涉水性能...     

用于混合动力控制的汽油机动态转矩建模仿真

针对混合动力系统能量管理及动力平稳传递控制策略开发的需要,以MATLAB/SIMULINK仿真软件为工具,建立了发动机平均值模型,模型能够根据发动机转速和节气门开度实时计算出发动机的稳态和动态转矩。在发动机动态试验台上验证了该模型,表明模型达到了需要的计算精度和实时性要求。对给定的转矩曲线进行动态跟随时发动机的节气门开度变化情况进行了仿真分析。模型可用于混合动力控制策略开发中的仿真及在线转矩估计,为并联式混合动力系统能量分配和动态协调控制中的发动机转矩反馈提供了基础。     

Mean Value WGT Diesel Engine Calibration Model for Effective Simulation Research

Recently, to improve vehicle fuel economy, as well as the performance of internal combustion engines, optimized system matching between a vehicle’s drivetrain and engine has become a very important technical issue. For this reason, the need for simulation research on engine and vehicle performance improvement has increased. But in general, since both engine simulation and vehicle simulation require initial engine calibration map input, a simple engine calibration method is required for the efficient configuration of various virtual engine calibration map setups. On this background, in this study, an example of waste gate turbocharger (WGT) cooled — exhaust gas recirculation (EGR) Diesel engine calibration using a test-based mean value engine model is presented as a suitable engine calibration map setting method. Also, the feasibility of an engine calibration model is confirmed through various engine tests. Using the simple model presented here, it is possible for diverse engine operating conditions and engine performance maps to be acquired.     

Vibration Control of a Passenger Vehicle Utilizing a Semi-Active ER Engine Mount

This paper presents vibration control of a passenger vehicle using an electronically controllable electro-rheological (ER) engine mount. A mixed-mode ER engine mount operating under the flow and shear modes is devised and manufactured. After establishing the dynamic model of the proposed ER engine mount, both field-dependent displacement transmissibility and dynamic stiffness of the ER engine mount are empirically evaluated. The ER engine mount is then incorporated with a full-vehicle model in order to investigate vibration control performance at the driver's seat position. The governing equation of motion of the full-vehicle model is formulated by considering engine excitation force, followed by designing a skyhook controller to attenuate unwanted vibration. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at idle speed are evaluated in the frequency and time domains.     

A nonlinear model for top fuel dragster dynamic performance assessment

The top fuel dragster is the fastest and quickest vehicle in drag racing. This vehicle is capable of travelling a quarter mile in less than 4.5 s, reaching a final speed in excess of 330 miles per hour. The average power delivered by its engine exceeds 7000 Hp. To analyse and eventually increase the performance of a top fuel dragster, a dynamic model of the vehicle is developed. Longitudinal, vertical, and pitching chassis motions are considered, as well as drive-train dynamics. The aerodynamics of the vehicle, the engine characteristics, and the force due to the combustion gases are incorporated into the model. Further, a simplified model of the traction characteristics of the rear tyres is developed where the traction is calculated as a function of the slip ratio and the velocity. The resulting nonlinear, coupled differential equations of motion are solved using a fourth-order Runge–Kutta numerical integration scheme. Several simulation runs are made to investigate the effects of the aerodynamics and of the engine's initial torque in the performance of the vehicle. The results of the computational simulations are scrutinised by comparisons with data from actual dragster races. Ultimately, the proposed dynamic model of the dragster can be used to improve the aerodynamics, the engine and clutch set-ups of the vehicle, and possibly facilitate the redesign of the dragster.     

Vibration Control of a Passenger Vehicle Utilizing a Semi-Active ER Engine Mount

This paper presents vibration control of a passenger vehicle using an electronically controllable electro-rheological (ER) engine mount. A mixed-mode ER engine mount operating under the flow and shear modes is devised and manufactured. After establishing the dynamic model of the proposed ER engine mount, both field-dependent displacement transmissibility and dynamic stiffness of the ER engine mount are empirically evaluated. The ER engine mount is then incorporated with a full-vehicle model in order to investigate vibration control performance at the driver's seat position. The governing equation of motion of the full-vehicle model is formulated by considering engine excitation force, followed by designing a skyhook controller to attenuate unwanted vibration. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at idle speed are evaluated in the frequency and time domains.